Per AppleInsider, work on OS X 10.7.5, the next performance and maintenance update for Lion, is far enough along that Apple is preparing to issue a preview of the software to its developers for testing.

A pre-release build of OS X 10.7.5 is set to be released to a limited number of members of Apple’s development community in the coming days, sources familiar with the software indicated on Monday. Public testing among all members of the Apple Developer Connection will likely begin soon after.

Details on what fixes or updates OS X 10.7.5 might include remain unknown. But any changes are likely to be relatively insignificant, as Apple is gearing up to launch the next major version of its Mac operating system, OS X 10.8 Mountain Lion, next month.

The last update to Lion, OS X 10.7.4, was publicly released in early May. It included a fix for a potential security flaw in FileBug.

OS X 10.7.4 also quietly added support for Retina display Macs, more than a month before Apple officially announced its next-generation MacBook Pro with 15-inch Retina display. That notebook began shipping last week with OS X 10.7.4 installed, featuring high-resolution support for icons and native applications.

Apple announced last week that Mountain Lion will arrive on the Mac App Store in July for US$19.99. Those who purchase a qualifying Mac between now and the date Mountain Lion hits the App Store will be eligible for a free upgrade to OS X 10.8.

If you’ve gotten your hands on the beta and have any feedback to offer, please let us know via the comments.